Double-acting percussion fuze provided with a safety device for projectiles



Feb. 4, 1958 c. VARAUD 2,821,925

DOUBLE-ACTING PERCUSSION FUZE PROVIDED WITH A 4 SAFETY DEVICE FOR PROJECTILES Filed April 16 1956 3 Sheets-Sheet l 2 90.05 Vale/40p Feb. 4, 1958 c. VARAUD 2,821,925

DOUBLE-ACTING PERCUSSION FUZE PR DED WITH A SAFETY DEVICE FOR PROJECTIL Filed April 16, 1956 5 Sheets-Sheet 2 Q H005 Vaem/a Feb. 4, 1958 I c. VARAUD 2,821,925 nousmqmwmc PERCUSSION FUZE PROVIDED WITH A SAFETY DEVICE FOR PROJECTILES Filed April 16, 1956 3 Sheets-Sheet 3 /A/l/ENTOE United Sttes atetit 2,821,925 PERCUSSIIQN FUZE PRQV J ED A- SAFETY DEVICE FOR PROIFECTHJES Ciggitie Varaud; Geneva, Switzerland; assignor to Ufa Universal Finanzierungs Austalt, Vaduz, Liechtenstein Application April16 1956', Serial No. 578,352

4' Claims. oi. 102-84 The invention relates more particularly, but notex d trstvety th ercussion fuies" for non-rotafive' projectiles st'tch' asthma Used in h owitzers with smooth tubeflor gttttsor ether-means which do not impart to the projectiles a fotative movement. v p

Theru'zewhicn forms the main objector the invention ileprovideti with: a"- safety device of the kind comprising a "toothed member connected with a clock-work hai ing a spring motor and an escapement balancewheel, rai'ttteethed member being maintained in a locking osition Eetween a plunger provided with a shoulder and an inertia block carrying a primer, in order to prevent an ili-"meti ercussion of the primer, not only during the f fis'portbut also after firing during a given space of time along the trajectory of the projectile. Said fuie a eh'a'raeterized- By' the fact that the toothed member eo'mprises'a slot having the shape of a button-hole of whit-Sh only the enlarged part allows the passage of at I'eaet one the two percussion members (shoulder hanger and inertia block carrying the primer), said en larged part coming in line with said percussion members, as 'a' result of the displacement of the toothed member e'ausetiby the dlock work, only after the firihg I, and atter a given space of time during the trajectory of the proj'e the, in order that the percussion may happen at the time ofthe' hit of the projectile, obturating means in connection with the toothed member being provided for, in order to prevent an ill-timed passage of the fire iirorh the primer to the detonator, not only during the transport but also by the firing and during a given space offihie along the trajectory of the projectile, locking means ofthe balance-wheel, being further provided for wiper-saidbalance-wheel until the firing.

The attached drawing shows by way of example, three foams of execution of the iuzewhich forms the object of the invention,

f is an axial cross section of the first form of ex uho'n' of the time, the members of said fuze being eking pos'i-ti'on before the firing. t

2; 3" and 4' are cross sections on a smaller scale res ectively- Fig*. S-is' a partial cross section along line V-V o'f Fig.1.

Fig; 6 is an axial cross section of the fuze', its merth hers b'e'ing in unlocked position after the firing and after a given travel of the projectile along its trajectory. I

Figs; 7 and 8 are cross sections along line VIP-VII and VII I VHI- of 6; illustrating the members (if the safety device in the unlocked position, i. e. in a position allowing the working of the fuze at the 'rhon'ient ofithe hit;

Figs *9 antttdillflsame a tar et scale, in top" View and cross sectiong a second form of execution of the time which the clack-work comprises a toothed sector.

Fig; 11? iiihsttates a cross section o'ri a lafg' er scale aph altsnglineXI -XI er'r'ri' 12" or third rot-1a ofexecution of the time, the members of the safety device being in looking position.

Fig. 12 is a cross section on a larger scale along line Xll XII of Fig. 11 illustrating the members of the safety device in the locking position.

Fig. 13 is a" partial cross section similar to that of Fig. 5 illustrating a variant of execution of the releasing device of the balance-wheel.

In the form shown in Figs. 1 to 8 of the drawings, a designates the body of the fuze, b (Fig. 2) the clockwork maintained in its position in the body a, by means of an elastic washer c bearing on a cap c screwed by 0 in the body a. The clock-work b is constituted by a frame b1 comprising two mounting plates [1 and b provided with pins (not sl'iowri). The frame b presents a diametral groove b in which slides loosely a toothed membefd constituted by a toothed rack, formed by sev eral' superposed small plates held together by means of fivet's d Each small plate is punched in one piece with a' toothing d and a slot d having the shape of a button-hole, the small and eiohgated part d of which serves as a guide, while the enlarged part or eye d is of circular shape. The toothing d meshes with a first pinion e of a gearing f and g pivoted in the mounting plates 5 and b and of which the last wheel g is constituted by the es'cape'ment wheel cooperating with a lever it made in one piece with the balance-wheel k Said balance-wheel pivots, by its central hole, around the pluhger i which constitutes its axis and which is located on the axis of the clock-work (Figs. 1 and 2). Said plunger comprises a rod i which ends in a percussion tip i and a shoulder i of a greater diameter. Said shoulder lies" oh the upper face d of the toothed rack d at the extremity of the guide (Z (Figs. 1 and 3). In the transport position before the firing, the plunger i cooperates with the inturned central conical part i of a piston j set under the action of a spring 1:, the action of which counterbalances the air pressure acting on the extremity f of the piston during the trajectory of the projectile; V

The toothed rack d is maintained in the position represented in Figs. 1, 2, 3, against the action of a spring motor (1 bearing on the bottom of a plug a screwed radially in the ogive of the body a, by an oscillating pin 1 hinged, by means of a ball and socket joint, on a piston m (Fig. 5) having a certain inertia and submitted to the action of a spring n. The upper extremity of the pin 1 is located, before the firing, on the path of one of the arms h of the balance-wheel and constitutes a stop preventing said balance-Wheel to oscillate and conseq'ue'n'tly' pr'eventih'g airy displacement of the toothed rack d. Said pin is maintained parallel to the plunger by a guide b5. 4

Ali inertia block 0, carrying'a primer 0 and maintained in itjs'posi'tio'n by a plug o is mounted axially in the body a of the fume, and is displaceable against the action of a return spring 0 which maintains the front face of a neck 0 of said inertia block, in contact with the under face d of the toothed rack d.

As illustratedin Fig. 1, the toothed rack d is thus interposed betwee'ri the shoulder i of the plunger i and the front end 0' of said inertia block: 0'. In this manner the primer o 'niay not be tired untimely.

' However a supplementary safety device, constituted by'ari' obturatiiig device, is located immediately under the primer o in order to prevent an ill-timed deflagration of said primer at the time of the firing.

Said obturat'ing device is constituted by an obturator formedby a metal tongue 2 (Figsa 1 and 4) of rectangular shape, located in a diametral groove q' made-in a washer q mounted in the extremity a of the tail a, of the haze.

A pin q determines the angular position of the washer q in the body a. A spring p located in a groove made in the washer q, exerts a thrust on a pin p fastened on the tongue 1. A mounting plate r maintains said spring p in position. The tongue p is provided with a hole 12., constituting a passage allowing the fire of the primer to reach the detonator when, after a given space of time after the firing, the displacement of the toothed member d releases a locking device of the tongue p, which immobilizes said tongue in the safety position (Fig. 4) against the action of the spring 9 Said locking device comprises a maintaining member constituted by a pin s, axially displaceable with respect to the body of the fuze and parallel to the axis of said fuze. Said pin s is guided on the one hand by its two extremities in corresponding holes made in the mounting plates [2 and r and on the other hand in a bearing a provided in the body of the fuze. The rear extremity of said pin s is provided with a conical tip 5 cooperating with a countersink having the shape of a cup, made in the tongue p. The front extremity s of said pin 3 abuts against the rear face d of the toothed rack d. in this manner, the tongue p is locked in the safety position illustrated by Figs. 1 and 4, and for which purpose the hole p, is not located in line with the primer Finally a plug 1?, screwed in the extremity :1 of the tail a maintains the washer q in position against any ill-timed displacement.

The working of the described fuze is as follows:

The ogive cap it being withdrawn, the fuze is in readiness for the firing.

By the start of the shot, the inertia pin 1 and its piston in, as illustrated in Figs. 6, 7, 8, move back as a result of their inertia and compresses the spring 11. The displacement of the pin 1 is of a sufiicient amount to cause the disengagement of said pin from its guide b Thus, the pin it releases the balance-wheel h which then oscillates under the action of the spring motor d and by the intermediary of the toothed rack d and the gearing f and g. Under the action of its weight, the pin 1 oscillates, so that its front extremity is no more located on the axis of the guide b made in the frame b Consequently, when the fuze, is no more submitted to the acceleration, the pin 1 may not come back again, under the action of the spring 71, in its primitive locking position but remains in the position illustrated in dash and dot lines in Fig. 6.

After a given space of time (about /3 of a second) the toothed rack d, driven by the clock-work, abuts at a in the inner groove [2 of the body a, and takes the position illustrated in Figs. 6 and 7. It follows that the extremity of the guide d is located, opposite the extremity of the pins s. Consequently, the spring p causes a displacement of the tongue p, and the countersink p acting on the conical tip s drives suddenly the pin s upwards and its extremity s enters in the guide d of the toothed rack d.

The tongue p being released, follows its displacement under the action of the spring p until said tongue abuts against the bottom of the groove a made in the tail a of the body a. In said position, Fig. 8, the hole 17 is now in line with the central hole of the plug 0 of the primer 0 so that by the working of the fuze caused by the hit, either by means of the direction effect (driving in of the piston j and of the plunger 1 into the primer) or by means of the inertia block 0 carrying the primer and which drives said primer towards the plunger i, the fire of said primer may, through said hole p reach the detonator (not illus trated).

It is to be noted that, for the safety position or trans port position of the device (Figs. 1 and 3), the shoulder i of the plunger i lies on the narrow part d of the slot made in the toothed rack d. Consequently, for said position of the toothed rack d, the plunger i is locked in the position shown in Fig. 1, and hence may not strike the primer. Further, for this position of the toothed rack, the front extremity of the inertia block 0 carrying the 4 primer, bears onto the face d or said toothed rack, so that said primer may not be displaced towards the plunger.

On the contrary, for the position illustrated in Figs. 6 and 7, the eye d the diameter of which is greater than the diameter of the shoulder i and of the diameter of the neck 0 of the inertia block 0, is located on the axis of displacements of the percussion members (plunger i and inertia block 0 carrying the primer), so that said members are released and that the percussion may occur either by means of a displacement of the plunger, or by means of a displacement of the inertia block 0 carrying the primer In the modification shown in Figs. 9 and 10, the toothed member d comprises a toothed sector pivoted along an axis ri and submitted to the action of a spring motor d Said sector d presents a slot having the shape of a buttonhole, the narrow part at, of which is arcuated and ends in an eye d As in the form of execution described hereinbefore with reference to Figs. 1 to 8, the toothed sector d is interposed (Fig. 10) between the shoulder i of the plunger i and the front extremity Q1 of the inertia blocko carrying the primer 0 The locking pin s of the obturator constituted by the tongue p, cooperates at d with said toothed sector d. The movements of the members of the fuze are similar to the movement of the members of the form of execution represented in Figs. 1 to 8. The similar members and elements are designated by the same reference characters.

In the modification shown in Figs. 11 and 12, the locking device of the obturator comprises a pin S rigidly fastened to the tongue or obturator p. The conical tip S of said pin S cooperates with a corresponding conical hollow chamfer 0 made in the rear extremity of the plug 0 screwed in the rear extremity of the inertia block 0 carrying the primer 0 Said plug 0 constitutes then the maintaining member of the locking device of the obturator.

After the firing, the toothed sector d, submitted to the action of its spring d oscillates around its axis ri and the eye :1 comes in line with the inertia block 0 and the plunger i. From this moment on, the front extremity 0 of said inertia block is released and may be displaced upwards under the action of the thrust exerted by the conical tip S of the pin S which is rigidly fastened to the obturator or tongue 12. From then on, said obturator may be displaced under the action of the spring 12 acting on the pin 2 and come into the service position for which the hole is located in line with the primer 0,, so that the fire of said primer will be capable to reach the detonator (not illustrated).

Fig. 13 illustrates a modification of the locking device of the balance-wheel h The pin 1 is rigidly fastened to the piston or inertia block m. Said pin 1 is split and its two arms present a self elasticity tending to spread said.

arms. When by the firing, the acceleration causes abackward movement of the pin, against the action of the spring n, and that consequently said pin disengages from its guide b the two arms of said pin move aside one from the other. The elastical deformation of the extremityof said pin hinders a new engagement of said pin in its guide, so that said pin can not come back, under the action of its spring n, in locking position of the balancewheel h It goes without saying that the split pin illustrated in Fig. 13 may be hinged on the inertia block m by means of a. ball and socket joint.

I claim:

1. In a double-acting percussion fuse having'a safety device of the kind comprising a toothed member provided with a slot having the shape of a buttonhole, a clockwork mechanically connected to said toothed member, a spring motor driving said clockwork, an escapement balance wheel controlling said clockwork, a shouldered plunger located at one side of said toothed member, a primer located on the other side of said toothed member in a position whereby said plunger may reach said primer only when the enlarged portion of said buttonhole-shaped slot is brought by said clockwork coaxial to said plunger, the combination with said safety device of an inertia block carrying said primer and having an end facing said buttonhole-shaped slot, said end being coaxial to said plunger and being retained against movement towards said plunger by said toothed member until the enlarged part of said buttonhole-shaped slot is brought by said clockwork coaxial to said plunger, whereby said toothed member constitutes simultaneously a locking means for the plunger and a locking means for the inertia block carrying said primer; an obturator provided with an opening to allow the passage of the fire of the primer, and means for controlling said obturator by said toothed member.

2. A double-acting percussion fuze as claimed in claim 1 and in which said locking device comprises a pin axially displaceable, a conical tip carried by one end of said pin, a conical surface cooperating with said conical tip, a plate retaining said conical surface in engagement with said conical tip, said plate abutting against one of the faces of said toothed member whereby, after a given displacement of said toothed member, said slot made in said toothed member gives passage to the end of said plate,

the displacement of which under the action of the spring acting on said obturator, causes the releasing of said obturator.

3. A double-acting percussion fuze as claimed in claim 2 and comprising a guide for said pin locking said balancewheel, the displacement of said pin caused by the acceleration being of a sufficient amplitude in order to disengage said pin from said guide.

4. A double-acting percussion fuze as claimed in claim 3 and comprising a ball and socket joint connecting said pin to said inertia block, whereby said disengaged pin oscillates under the action of its weight and comes out of line with the axis of said guide.

References Cited in the file of this patent UNITED STATES PATENTS 1,726,325 Varaud Aug. 27, 1929 2,116,820 Birkigt May 31, 1948 2,448,228 McCaslin Aug. 31, 1948 2,531,121 Fink Nov. 21, 1950 2,699,118 Leroy Jan. 11, 1955 FOREIGN PATENTS 126,387 Great Britain May 15, 1919 107,411 Switzerland Nov. 1, 1924 

